net/mlx4_en: Fix mixed PFC and Global pause user control requests

[pandora-kernel.git] / mm / vmscan.c

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 86eb848..4de949b 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1085,6 +1085,7 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
 
                if (PageDirty(page)) {
                        struct address_space *mapping;
+                       bool migrate_dirty;
 
                        /* ISOLATE_CLEAN means only clean pages */
                        if (mode & ISOLATE_CLEAN)
@@ -1093,10 +1094,19 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file)
                        /*
                         * Only pages without mappings or that have a
                         * ->migratepage callback are possible to migrate
-                        * without blocking
+                        * without blocking. However, we can be racing with
+                        * truncation so it's necessary to lock the page
+                        * to stabilise the mapping as truncation holds
+                        * the page lock until after the page is removed
+                        * from the page cache.
                         */
+                       if (!trylock_page(page))
+                               return ret;
+
                        mapping = page_mapping(page);
-                       if (mapping && !mapping->a_ops->migratepage)
+                       migrate_dirty = mapping && mapping->a_ops->migratepage;
+                       unlock_page(page);
+                       if (!migrate_dirty)
                                return ret;
                }
        }
@@ -3015,6 +3025,11 @@ static int kswapd(void *p)
                                                &balanced_classzone_idx);
                }
        }
+
+       tsk->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD);
+       current->reclaim_state = NULL;
+       lockdep_clear_current_reclaim_state();
+
        return 0;
 }